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对TDI生产中现有的光气回收工艺进行了分析,提出了无压缩机的光气回收工艺。原工艺的特点是在光气化回路压力比较高,而在脱气和气提工序压力低;从后两工序分离出的气体需要采用两级压缩的工艺来升高压力,然后进入高压吸收塔进行光气回收,回收的光气重新返回到光气化回路。光气两级压缩不仅设备投资大,而且在生产中容易发生故障,造成整个系统的波动或者是停车,危险性较大。无压缩工艺去除了压缩工序,增加了深冷器,对反应分离罐分离出来的光气进行了深冷,使大部分光气在此处冷凝为液相返回到光气化回路。剩余少量光气和脱气塔、气提塔来的光气用吸收塔进行吸收。吸收塔改用微正压操作。吸收下来的光气经泵加压后返回到光气化回路。经Aspen模拟,新工艺能够满足工艺要求,减少设备投资,并降低系统的能耗。
The existing phosgene recovery process in TDI production is analyzed, and the phosgene recovery process without compressor is proposed. The characteristics of the original process are that the pressure in the phosgenation circuit is relatively high and the pressure in the degassing and stripping processes is low; the gas separated from the latter two processes needs to adopt a two-stage compression process to increase the pressure and then enter the high pressure absorption tower Phosgene recovery, recovery of phosgene returned to the phosgene loop. Phosgene two-stage compression not only equipment investment, but also prone to failure in the production, resulting in fluctuations in the entire system or parking, a greater risk. No compression process to remove the compression process, the addition of a cryogenic cooler, the separation of the reaction tank phosgene was cryogenic, so most of the phosgene condensation in the liquid phase to return to the phosgene loop. The remaining a small amount of phosgene and degassing tower, phosgene to the absorption tower with absorption tower. Absorption tower switch to slightly positive pressure operation. The absorbed phosgene is pressurized by the pump and returned to the phosgenation circuit. Aspen simulation, the new technology to meet the process requirements, reduce equipment investment and reduce system energy consumption.